1. Field
The present disclosure relates generally to aircraft and, in particular, to airfoils for aircraft. Still more particularly, the present disclosure relates to a method and apparatus for a variable pitch airfoil for an aircraft.
2. Background
An unmanned aerial vehicle (UAV) may be an aircraft that may fly without human operators being present in the aircraft. Unmanned aerial vehicles may come in a number of different shapes, sizes, configurations, and/or characteristics. Unmanned aerial vehicles may, for example, take the form of fixed wing aircraft and/or helicopters.
Unmanned aerial vehicles may be controlled from a remote location. At this remote location, a human operator or a program executed by a computer may generate commands for the unmanned aerial vehicle. Unmanned aerial vehicles also may be controlled using a program running on a computer or other controller on the unmanned aerial vehicle.
Unmanned aerial vehicles may be used for a number of different purposes. Currently, the largest use may be for military applications. Unmanned aerial vehicles may be used to perform missions that may include, for example, without limitation, reconnaissance missions, attack missions, and/or other suitable types of missions.
Unmanned aerial vehicles also may be used in a number of civilian applications. For example, without limitation, unmanned aerial vehicles may be used to perform surveying, firefighting, and other suitable types of missions.
In some cases, it may be desirable to reduce the footprint or size of an unmanned aerial vehicle prior to its use. For example, it may be desirable to pack or stow an unmanned aerial vehicle for launching. The launching of the unmanned aerial vehicle may be by hand, air drop, missile, gun, or other suitable types of delivery systems.
In meeting these types of goals for launching and/or transporting unmanned aerial vehicles, inflatable components have been developed. These inflatable components may provide for more compact packaging for stowing, transportation, and/or launching of the unmanned aerial vehicles. Additionally, these inflatable components also may be designed to provide a desired speed of deployment, while reducing the mass and complexity of the components.
For example, without limitation, wings have been designed using inflatable structures. With inflatable wings, a non-mechanical mechanism for stowing and deploying these types of structures may be present. Further, with inflatable wings, controlled deformations of the wings may be performed using actuation systems that may be located on or within the inflatable wings. These systems may deform and/or otherwise bend the wings to provide the desired amount of lift and/or control of the movement of the unmanned aerial vehicle.
With inflatable wings, durability may be a concern. The durability may involve the ability of inflatable wings to survive when launched by a delivery system, such as a gun or missile. Additionally, the durability of these components also may involve the ability of the components to be reusable over a number of deflations and inflations of these components. The durability of these components also may involve the storage of the components in either a packed or inflated state for extended periods of time in extreme conditions.
Also, when an unmanned aerial vehicle lands or impacts an object, the survivability of the inflatable components may be desirable. Other durability goals may include, for example, without limitation, the ability of inflatable wings to function as desired with different levels of wind gusts and/or currents.
Accordingly, it would be advantageous to have a method and apparatus which takes into account one or more of the issues discussed above, as well as possibly other issues.